The advantageous results that are derived from the storage of fodder and other farm products in agricultural storage bags are now well documented. For example, agricultural storage bags having diameters of up to 12' or more and having lengths of up to 120' or more are now in common usage throughout the United States and numerous foreign countries. Apparatus for filling agricultural storage bags with compressed fodder or other materials is shown and described in U.S. Pat. No. 4,337,805 granted to Ag-Bag Corporation on July 6, 1982, the disclosure of which is incorporated herein by reference.
The silage compression machine shown in U.S. Pat. No. 4,337,805 includes a hydraulic motor which is actuated by pressurized hydraulic fluid supplied from a hydraulic pump. The hydraulic pump may be driven by the power take-off of a conventional farm tractor. Such an apparatus requires the use of a hydraulic fluid reservoir for receiving spent hydraulic fluid from the motor and for supplying hydraulic fluid to the pump. U.S. Pat. No. 4,256,031 granted to Blair Manufacturing Company on Mar. 17, 1981, discloses a hydraulic fluid reservoir construction for silage compression machines wherein the reservoir comprises part of the tunnel which directs compressed material into an agricultural storage bag. According to the disclosure of U.S. Pat. No. 4,256,031, heat from the hydraulic fluid in the reservoir is transferred through the tunnel wall and into the material which is being compressed into the agricultural storage bag.
In actual practice, it has been found that the hydraulic fluid reservoir construction disclosed in U.S. Pat. No. 4,256,031 incorporates numerous disadvantageous characteristics. First, although many silage compression machines require the use of a hydraulic fluid reservoir, such is not always the case. For example, some silage compression machines are driven directly from the power take-off of a farm tractor, while other silage compression machines incorporate an engine, thereby completely eliminating the use of a separate prime motor. When the hydraulic fluid reservoir construction disclosed in U.S. Pat. No. 4,256,031 is used for silage compression machines requiring a hydraulic fluid reservoir, a completely different tunnel construction must be provided for silage compression machines which do not require such a reservoir. Perhaps more importantly, in actual practice it has been shown that only a negligible amount of heat is transferred out of hydraulic fluid contained in a reservoir constructed as shown in U.S. Pat. No. 4,256,031 and into material that is compacted into an agricultural storage bag by the silage compression machine.
The present invention comprises a hydraulic fluid reservoir construction for silage compaction machines which overcomes the foregoing and other difficulties long since associated with the prior art. In accordance with the invention, a self-contained hydraulic fluid reservoir may be mounted adjacent to the tunnel of a silage compression machine, but does not comprise an integral part of the tunnel construction. This permits the use of the same tunnel construction for all types of silage compression machines. Additionally, the reservoir is mounted in a spaced apart relationship with respect to the tunnel wall, thereby facilitating heat transferred from the hydraulic fluid contained in the reservoir to the ambient atmosphere by means of a thermal siphon created by the spatial relationship between the tank and the tunnel wall.